In this guide, you’ll learn everything about solar pool heaters you always wanted to know but were afraid to ask! We’ll answer the questions like how they work, what the benefits are, things to look for when shopping, as well answer some frequently asked questions that bothered consumers. By the end of the guide, we’ll review the TOP 5 Best Solar Pool Heaters worth buying.
Solar pool heaters generally work in one of three ways. Some are still electric, using solar power as their supply, which is the best way to apply solar to heating much of anything. However, this relies on a lot of direct sunlight, as well as a battery array to store the power to continue functioning into the night.
The other two are more direct, transferring the thermal energy of the sunlight directly into heat in the water. This is done in one of two ways – through an exchange chamber, where it’s heated by focused light and circulated back into the pool, or through sheeting which sits atop the water’s surface. The latter transfers the energy directly down into the water, while also trapping it.
Sometimes, you have no choice but to go with an above ground pool, due to zoning or lack of space in your yard for a full sized in-ground pool. These aren’t the same, and no owner of an above-ground pool would argue otherwise. But, they can still be made quite nice with some effort. With their larger volume to surface area, they tend to stay warm better than in-ground pools. Exchange heaters, which flow water through a heating chamber, can heat these very efficiently, though it generally takes an array of them if they’re small.
For in-ground pools, surface sheets are going to be far more effective. This is a slow process, but the amount of heat they’ll trap, especially when these sheets are kept over the pool during any disuse, means that you’ll have warm water for quite some time when you’re ready to use it.
The problem with solar energy is it’s not as exact as electric or gas heat. While the amount of energy put out by the sun is macroscopically more or less constant, variables such as atmospheric conditions, weather, and randomness in water chemistry mean that there’s no way to predict how hot the water will get from them.
This also varies widely depending on the amount of water, the surface-to-volume ratio, and the size/volume of the heaters in use. Sheet heaters on a pool’s surface tend to raise it by about 10-15 degrees, sometimes more on a really sunny and hot day.
Exchange heaters, however, can get water very hot, even hotter than a hot shower if they get the right amount of heat. I’ve seen these heaters put out water that was well over 100 degrees. Don’t fear – they tend to cycle less than half the pool over a day, meaning this hot mixes with the cold for a nice temperature.
As said above, with solar energy, you can’t really predict this without some expensive meteorological equipment that can give you solar output over a period of time, and produce trends which you can convert into thermal units.
With surface sheet style heating, you want exactly the amount of material as the surface area of the water. For above ground pools, you will possibly want to line the sides of the pool with this material as well.
For exchange heaters, you’ll want to look at the amount of water that tends to pass through it in a period of time. You want it to put at least a third of your pool’s volume of water through it per day, if not more. It doesn’t have to cycle every drop of water – the water coming from exchange heaters will, theoretically, actually be a bit warmer than you want the pool to be, and the dilution and exchange with the cooler water will result in an overall even-temperature pool.
How to winterize solar pool heater?
Disconnect the water from the heater, and drain it, make sure it’s dry, and cover it with an insulating tarp. If you live in a place where it freezes, do not try to solar-heat your pool in the winter.
How to install a solar pool heater on the roof?
Usually, there will be some mountings that fasten down – screws or nails, and then two pipes, one leading in from the pump, one leading back to the pool. It’s honestly pretty easy usually.
Hereinbelow, we’ll cover the solar pool heaters we’ve found online. We’ll review all kinds of form factors and touch on various price categories from the most affordable (around £20-£30) to the most expensive.
This one doesn’t pretend it doesn’t need a pump, including a small portable one with the unit. This is a simpler solar approach, using the black material to trap the heat of the sun, and thus ambiently heat the water that runs through it.
For something with less volume, like an above ground pool, these are surprisingly effective and pretty quick. These tend to be fragile though, but with their affordability, that’s less of an issue than it would be for other models.
Features
Performance
I have a friend whose yard is just too small for an in-ground pool. But his above ground pool is quite nice, with wood finish, landscaping around it, and a partial deck connecting to it. He has a heater very similar to this, albeit about twice the size (this one is 47x47”). It takes about half an hour, on a hot, sunny day, to get his pool comfortably warm with it, so I’d say an hour with this one, for the average above-ground pool.
These work surprisingly well.
Conclusion
These do not work for in-ground pools, and I’d recommend using two or three of these to heat an above-ground pool of any significant size. This relies on the intensity of the sun to heat light-absorbent materials, which means it is much more dependent on the intensity of sunlight provided. So, these only work in a hot, sunny summer if you live in a place with seasons. You’ll want something electric as a backup otherwise.
Here are the reviews from YouTube bloggers who tested the solar pool heaters and have found them effective and worth buying.
Matt Lundquist: "We're use the Intex solar heater. This is a mat style, it is roughly four foot by four foot, it's like 47 inches and it comes with the map. It comes with one hose. This hose is about 2 foot long. And it's the engine, and quarter diameter comes with a diverter valve the that's on the mat itself and the valve diverts the fluid away from the solar array.
The solar heater works really well. The solar cover helps a lot too, but the heater, actually, you can feel warm water coming out, even after an hour of it running. I thought it would be warm at first and then dissipate. But it, actually, stays one which is pretty amazing and sometimes in the morning, when this doesn't even have Sun over here."
Famous Tool: "At the first position of our list we have Sun Heater S120 Universal Solar Pool Heater. Sun heater zone 120u provides an amazing alternative to heating your pool. Especially during the spring and autumn seasons. A solar heater for pools can be designed to fit in ground or above ground purposes however. The Sun Heater is suitable for both options.
The system is designed with a 2 feet x 20 feet long solar heating collector that is made of a lightweight flexible black polypropylene. The collector has been also designed with the tube construction that creates a larger surface area to optimize heat transfer through the pipes to your swimming pool.
The solar heating system is able to raise water temperature up to 60 degrees Fahrenheit.
Depending on solar irradiance values on the location and works perfectly with most pool pumps. The solar heater for pool has been designed with high grade materials that can resist harsh weather conditions. Moreover the heating system includes around 1.5 header manifold and is attached with a rubber coupling.
The solar heating system is ideal for above ground pools below 18 feet."
Pros
Cons
Nothing says luxury and success quite like having a private swimming pool in your yard. Sure, the above ground pools are pretty inexpensive, but are those real pools? Are that? Most would argue that no, they’re not. No, you want a nice, deep in-ground pool you can relax beside and enjoy the relaxing waters for at least half the year, right? Well, there’s a problem with that idea, and it’s not the expense of installing one (honestly, it’s not that expensive these days), nor is it the maintenance (which isn’t rocket science either). No, the thing is, water gets darn cold, even in the summer.
The thing with water is, it doesn’t store heat very well for long periods of time. This is why water heaters for your home plumbing have to actively maintain the hot water supply, and why it can be depleted by too many people taking excessively long showers.
With a pool, this problem is considerably magnified. The issue is surface area, which a pool has plenty of. This provides a lot of space for heat transfer back into the air. Just as hot air rises, so does hot water, which will collect at the surface, and shed the heat into the air through evaporation or simple thermal radiation.
Even on a sunny, relatively warm day in midsummer, you may be shocked when you jump into the water to come up gasping as the warmth your toes had reported extended, at best, six inches into the depths. While the idea of cool water on a hot day is nice, as human beings, our idea of “pleasant cool” isn’t very cool – the high seventies, for water, are pretty chilly indeed.
This calls for a heating system, which not only can abate the chill of water in the summer but can greatly extend the amount of the year you can enjoy your pool. Even in areas that have potent winters, pool owners often get an extra month of swimmable water out of a good heating system.
Of course, a lot of these heating systems are similar to home water heaters, with a water exchange system and a heating reservoir tank. But, this eats a good bit of power, so a lot of people find the idea of a solar heater to be appealing.
Solar or electric heater?
Honestly, I’ll recommend electric every time, as solar power is the very definition of unreliable. But, in really sunny places like California, you can see savings from using solar.
What size solar pool heater do I need?
This depends on the type of pool. Honestly, look at your gallon count, and your form factor, and compare that to a given pump. There is no answer to this question that’s true for everyone.
Is it really profitable to obtain a solar heater for an above ground pool in particular?
Potentially, though in climates that aren’t exceptionally sunny, it’s more of a reduction of your existing heating bill, not an elimination of it.
How do I assemble a complete solar heater?
This varies wildly, but most of them merely require a frame to be put together, and lines connected. A lot of them don’t even require this, simply needing to be fastened and lines connected.
But which heaters are the best for sunny California where it is almost always warm; and other states where the sun also shines during the day but the air temperature is lower or drops sharply at night?
I grew up in LA, and I now live in Florida. Contrary to what people from neither place may think, they’re very different climates. The presence of palm trees means little besides the lack of actual freezes in winter. Growing up in LA, we had a solar pool heater array, though we also had an electric heater as a backup.
In California, these solar heaters are actually fantastic, because you really only get two types of skies, at least in the southern part of the state where I was – stormy and rainy, or extremely sunny. You get so much sun, in fact, that we had to actually put a shut-off valve on the heater, because that water in mid-July at 2 in the afternoon, would scald you coming out of that thing. I still, decades later, have a scar to prove that in fact.
Florida, however, is a different kettle of fish. Does it get hot here? Oh yes, it gets very hot, and humid too. But, it’s not as sunny as people actually think. Florida, and indeed most of the East Coast, gets a real mixed bag of weather. It can be cloudy and do absolutely nothing, it can rain for days. Solar power of any sort, here, is not very reliable.
Another problem, which is why I said they’re theoretically low-maintenance, is the algae here. It’s in the air, and you don’t notice it, until it grows on window screens, in pools, and yes, in those hot, incubating solar panels as well.
My personal conclusion for places that aren’t the desert or Southern California is – yes, do install one. Be sure to treat the water with anti-algal chemicals too. Relax, they’re harmless just don’t drink shots of them. But, also have an electrical heater as a backup – believe me, you’ll need one at some point.
Conclusion
I won’t pretend I’m a big fan of depending on solar energy in most parts of the world. These sorts of technologies are absolutely fantastic in places that’re sunny far more often than not – deserts particularly. Southern California, which is, in fact, a desert kept artificially green, benefits from solar to reduce smog. But, for the rest of the world, I wouldn’t say it’s useless – it’s a great supplement to reduce your heating costs, but you should have an electric heat source to supplement or replace it when the sun’s too weak. Accept this inevitability, and any one of these should actually be a big help.
